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000 
FXUS61 KBGM 090209
AFDBGM

Area Forecast Discussion
National Weather Service Binghamton NY
909 PM EST Sun Dec 8 2019

.SYNOPSIS...
A large storm moving thorough the Great Lakes will push warm air
and rain into the area Monday and Monday night. Colder air will
follow the storm on Tuesday bring snow showers that will linger
into early Wednesday.

&&

.NEAR TERM /THROUGH MONDAY NIGHT/...
905 PM update...

Warm air advection is increasing this evening, and mesoscale 
models are forecasting warmer early morning temperatures across
our area. 

We still expect spotty freezing rain to mix with rain and a few
wet snow showers over northeastern secions of Oneida County and
portions of our southeastern forecast area. However, we 
decreased the duration and expanse of the freezing rain due to 
warmer temperatures moving in.

Previous discussion...

Lee wave develops rapidly into a lake runner passing well west 
of the area. Rapid deepening develops along with a nice jet 
streak with the forecast area being in the favorable entrance 
region. So precipitation explodes over the area Monday as the 
low races up into Quebec.

Very cold last night with a good snow cover could keep road
temps very cold and allow for a bit of freezing rain tonight, 
mainly over the extreme northern CWA despite the strong warm 
advection. No large blocking high keeping the cold air locked as
the rain moves so expect a pretty quick warm up. Not
anticipating the need for an Advisory at this time, but it 
could be handled with an SPS. 

Rapid movement of the system will limit rainfall amounts but
snow melt with the rain will bring rises below caution stage.
A couple of spots could exceed that or come close, namely the 
Black river in Boonville and some headwater points on the Upper
Susquehanna and Delaware. Hydro watches should not be needed. 

Rain will become more showery ahead of he cold front Monday 
night as a dry slot develops along with the upper jet structure
pulls out to the north.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
300 PM Update...No major changes to the short term period. Cold
front still rather slowly sags through the area during the day
Tuesday, with gradually falling temperatures in central NY by
midday or early afternoon. Temperatures begin to fall by late
afternoon across NE PA. Before the front moves through it will
be another very mild day, with highs 45-50 in CNY, and 50-55 for
NE PA. Temperatures fall into the 30s by sunset across CNY, but
still 40-45 for NE PA. Rainfall amounts look light on Tuesday,
generally under a quarter inch. Some wet snow could mix in
across the hilltops of CNY late in the day. WSW winds become NW
by afternoon; 6-12 mph with gusts to around 20 mph.

Tuesday Night: The mid level front stalls along just southeast
of our forecast area Tuesday night. Cold air continues to
filter in from the NW during the evening and overnight. This
creates a bit of an anafront situation, as another weak wave
rides up along the boundary from the south. Latest guidance is
still struggling with just how much and how far to the NW
precipitation will redevelop Tuesday night. Used a blend of the
latest guidance for now. As cold air advection continues,
temperatures should be cold enough to change the lingering
precipitation over to snow by the late evening hours (even across
NE PA). Again, still plenty of uncertainty but chances are 
increasing for at least some accumulating snow (perhaps 1-3") 
mainly southeast of Binghamton, across NE PA and the southern 
Catskills especially. Will continue to monitor the latest 
trends on this scenario closely. At the same time, as the cold
air deepens lake effect snow shower will also develop along and
north of the NY Thruway near Syracuse and Rome. Some minor snow
accumulations are also possible up here. Overnight lows will be
in the 20s.

Wednesday: The slow moving front should finally completely exit
the area off to the south and east in the morning. 850mb
temperatures fall to around -12C through the day. Along with 
the cold there will be a breezy west wind and more lake effect 
snow showers. A weak clipper system passed by well to the north 
across Ontario, but this will likely act to shift the lake 
effect snowbands around from south to north through the day. 
High temperatures only manage to reach the mid-20s to lower 30s.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
310 PM Update...No major changes to the extended either with
this update. Lake effect snow showers continue Wednesday night
and early Thursday before high pressure builds over the region.
Dry weather late Thursday through much of Friday. Still watching
a system approaching from the south along the coast Friday night
into Saturday. High pressure slides off the coast prior to this
system arriving, bringing a warm south-southeast flow. Trended
the weather grids toward more rain with this system, with warmer
temperatures expected aloft and at the surface.

Previous Discussion Below


345 AM Update...
Very cold conditions are anticipated Wednesday through 
Thursday, with lake effect snow showers for some parts of the 
area, followed by moderating temperatures as we head into the 
weekend.

Arctic air mass will take over Wednesday and especially
Wednesday night-Thursday as the Canadian high builds over the
area. Boundary layer flow ahead of the high will be westerly or
perhaps even west-southwest at times, which will tend to direct
heavier lake effect snows mainly north of the area Wednesday
morning through evening. That said, clusters of Lake Erie snow 
showers and flurries can still be anticipated for much of the 
area, especially Central New York. Westerly winds will gust
15-25 mph Wednesday with highs of mid 20s to lower 30s.

Later Wednesday night into early Thursday, subsidence inversion
of incoming high will begin to lower yet the dendritic growth
zone will also be contained underneath it. As low level flow
veers a bit more northwesterly ahead of the high, lake effect
off of Lake Ontario may advance across the NY Thruway late
Wednesday night, with at least light multibands pressing further
southeast Thursday morning. Lows will be in the upper single
digits to upper teens.

The high pressure and its very dry air eventually win out,
ending lingering flurries by afternoon and allowing for at least
some sunshine. Highs Thursday are expected to be only 20s
areawide. However, we will get into return flow as that high
passes by, with moderating temperatures Friday-Saturday. Friday
appears dry, but there is plenty of uncertainty during the first
half of the weekend as an upper trough digs to our west, and
advects in moisture and thus possible precipitation. This may
include a snow to mix to rain transition.

&&

.AVIATION /02Z MONDAY THROUGH FRIDAY/...
VFR expected through the night. Only aviation concern remains 
the LLWS as southeast winds at the surface are topped just 
above the boundary layer with a strong southwest wind developing
ahead of the approaching trough. Lowered ceilings and 
visibilities will develop late tonight after about 11Z and on 
into the day Monday as rain moves into the area. Conditions will
eventually become IFR as the rain becomes heavier through the 
rest of the morning. The heavier rain shifts to the east Monday 
afternoon and the rain becomes more scattered. The threat for 
MVFR fog will likely increase through the afternoon as the near-
sfc layer becomes saturated. Ceilings may also drop to IFR or 
lower. LLWS will likely continue through the day tomorrow as a 
secondary push of 50 kt winds around 2-3k ft arrives after 19Z.

Outlook...

Monday night into Tuesday...Restrictions likely in rain.

Wednesday...Restrictions possible in snow showers.

Thursday and Friday...VFR expected.

&&

.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.

&&

$$

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